AC troubleshooting 2003 JSW

[MATPOC]

I'm fairly experienced, had ASE certifications at some point, AC license when R12 was impossible to get, but I have zero experience with newer cars, left the trade in 2001.
2003 Jetta Wagon, AC worked fine last year, pretty sure it was on couple weeks ago but it never really got warm outside till today and I got nothing... System has good pressure, fans turn on when AC button is pressed but compressor doesn't cycle, and I don't even know where the fuses and relays are...
I know it's common in Hondas for a relay to fail, usually a sign of failing clutch, wondering if there is some common failure on those cars. I need to get this fixed ASAP, leaving on a trip in couple days, heading south, not keen on driving 2,000 miles with windows down

 

[Windex]

pressures are good, but the compressor doesn't cycle? that doesn't make any sense. Pressure is almost meaningless in an ac system with no compressor action. Means that there is some refrigerant in the system, but not necessarily the right amount.

If the fans come on, that's good. next step is to get down to the compressor and see if the electrical connector is getting 12v. if not, then work back to the relay. If yes, then you have a bad compressor clutch coil.

 

[MATPOC]

I mean it has pressure, can't say how much freon is in it, but was working fine all last summer, so not overfilled, and it high enough that I should get some compressor cycling, which I got none.

So it's either sensors, relay, clutch, wiring or perhaps something else? Compressor is at the bottom, not exactly easy to access, I don't even know where the fuse box is, nothing marked.

I'm sure I can figure this out on my own but because time is limited and I still got to pack or perhaps change of plans I was hoping for some quick insight.

 

[Zak99b5]

Compressor on the bottom makes it fairly easy to access.

As stated above, if the clutch doesn’t engage, check for voltage at the plug (back probe with it connected is best), amd listen for the clutch to click when it’s supposed to turn on. Also, ohm out the clutch and/or supply it with 12vdc to see if it’s working.

I had to replace my a/c clutch, amd it’s not too bad of a job.

 

[P2B]

I mean it has pressure, can't say how much freon is in it, but was working fine all last summer, so not overfilled, and it high enough that I should get some compressor cycling, which I got none.

So it's either sensors, relay, clutch, wiring or perhaps something else? Compressor is at the bottom, not exactly easy to access, I don't even know where the fuse box is, nothing marked.

I'm sure I can figure this out on my own but because time is limited and I still got to pack or perhaps change of plans I was hoping for some quick insight.

Open circuit compressor clutch coil is a relatively common failure mode that fits your symptoms, easily checked with a multimeter. Coil can be replaced without discharging the system.

Failing that, the first post in this thread links to AC troubleshooting procedures.

Check your radiator/condenser fan operation NOW

Mk IV Manual AC electrical & cooling fan troubleshooting and repair Now is the time of the year to check that your pair of electric fans that provide cooling for both the radiator and air conditioner condensor are functioning. Do not needlessly age your Air Conditioning compressor by running it...

forums.tdiclub.com

 

[BobnOH]

Yes, for troubleshooting, try the link P2B provided. Lots more than just the fan bidness.

 

[MATPOC]

Well, good news it's working now, got the car on the lift, checked coil (3.2 ohm) put 12V across the terminals and it engaged, checked all fuses, connectors, started it up and it works now. Bad news is that I still have no clue what caused it, intermittent fault is hard to trace, fingers crossed it stays working for the next week, going to Deals Gap (The Dragon) Had this same issue with my Honda in the past where I repaired something and AC crapped out again when I got to TN, had to drive back 1000 miles with windows down, it gets annoying...
Below is a diagram I found and uploaded, hope it's helpful if someone needs it in the future